Drill post



E. B. LEAF Jan. 20, 1953 DRILL POST Filed Dec. 24, 1948 @HEM N.

Patented Jan. 20, 1953 UNITED. STATES PATENT GFFICE DRILL POST Earl B.Lear, Detroit, Mich., assigner to Chicago Pneumatic Tool Company, NewYork, N. Y., a corporation of New Jersey Application December 24, 1948,Serial No. 67,120

5 Claims.

This invention relates to drill posts and more particularly to a drillpost assembly for use in the drilling of earth formations such as rock,coal and the like.

In the drilling of rock or coal it is frequently necessary to use a postfor the support of the drilling apparatus, since the weight of ordinarydrilling machines is too great to be carried for any length of time bythe operator, especially when drilling holes other than those which arevertically downward.` Various types of drilling posts are used, rangingfrom a simple post inserted in a hole to posts which are adapted to beanchored in a hole by means of expanding the anchoring end of the postafter it is inserted in the hole. In the simple type of post it isimportant that the post and hole be of good fit if any sort of stabilityis to be achieved. This type of post is not entirely satisfactory,especially when mounted in other than a horizontal surface, since thereis a tendency for the post to be gradually forced from the hole as aresult of the forces of reaction which act parallel to the axis of thepost. In the usual expansion type of post, While provision is made bymeans of the expansion feature to counteract the forces of reactionacting parallel to the posts axis, there is not a rigid support, sincethe Weight of the drilling apparatus and its distance from the Worksurface are suicient to develop a moment of force about the base of thepost, of such magnitude that it cannot be eilectively counteracted bythe post anchoring portion.

To avoid the inherent disadvantages of the drill posts as discussed, thedrill post assembly of the present invention operates to effectivelycounteract all the forces of reaction acting'on the drill post, Whichare likely to occur in normal use. The drill post assembly features ananchoring means which has a first portion adapted to effectively resistthe forces of reaction which operate parallel to the axis of the postassembly, and a second portion which is adapted to eiectively counteractthe forces of reaction transverse thereto.

The drill post assembly of the present invention has been foundespecially useful in quarry Work where tripod drill mountings wereformerly used in drilling vertical or horizontal holes. It is difficultwith a tripod mount to drill holes near a vertical surface. However,with the use of this drill post assembly and a long cross-arm mountedthereon, holes may ,be easilyv drilled close to a vertical rock surface.

This drill post assembly is particularly well adapted for channeldrilling. Two of these drill post assemblies may be set in the surfaceof the rock, which is either'vertical or horizontal, at about eight toten feet apart, and a long channel bar can then be mounted on the drillpost assemblies in the manner which is usual in channel drilling. Ingeneral, this drill post assembly can be used in most places which areinaccessible to other types of drill mountings.

An object of this invention is to provide a new and novel drill postassembly, which serves as la rigid and stable drill supporting means.

Another object of this invention is to provide a new and novel drillpost assembly which can be readily and securely anchored in either ahorizontal, vertical or oblique working surface.

A further object of this invention is to provide a drill post assemblywhich can be used in channel drilling and can also be readily used inplaces inaccessible to other types of drill mountings.

In order that the invention may be readily understood and carried intoeiiect reference is made to the accompanying drawing in which:

Fig. 1 is a perspective View of the drill post assembly.

Fig. 2 is a vertical full-section view of the anchoring means thereofshown in operative position.

Fig. 3 is an enlarged perspective view of a washer used in the drillpost assembly of Fig. l,

and

Fig. 4 is a cross-sectional view as seen from line 4-4 of Fig. 2.

The illustrative drill post assembly comprises a post or column memberI0 supported by an anchoring means H. The column member sup ports across varm i2 Which may be clamped on the column member in any selectedposition of adjustment by means of bolts I3. The cross arm serves as asupport for any suitable drilling apparatus, such as a rock drilldrifter (not shown). The column member is most conveniently fashionedfrom metal tubing, one end being securely fastened to the anchoringmeans by means of a shrink t which can be reinforced by welding iidesired.

The anchoring means l l comprises a rst portion I4 slidably arranged inpart Within a second portion l5, the second portion being locatedbetween the first portion and the column member l@ as shown.

The rst portion comprises an expanding collet l5, which is tubular inform, and is `adapted to surround in part a collet expansion means ordraw bolt il, and resilient means `in the form of a compression springle. The expanding collet has a laterally expansible part comprisingsegments formed by three equispaced longitudinal slots I, extending fromthe lower extremity to a distance of a little more than one half thelength of the collet. The inside surface on each of the three segmentsat the lower end of the expansible part is arranged to provide a conicalsurface 2Q, which is tapered to Contact the conical surface portion ofthe draw bolt, as will later be discussed. Just adjacent the minimumdiameter of the conical surface, a shoulder 2| is provided for theabutment of the compressive spring I8. On the outside surface of each ofthe three segments is arranged a series of parallel grooves orserrations 22. The upper end of the collet has a cylindrical exteriorsurface 23, which is machined to provide a sliding i'lt with theinterior surface of the second portion I5.

The second portion comprises a rectangular yoke-like body 213 having atubular protrusion at the upper end, and a tubular protrusion 25,frusto-conical in part, at the lower end. The protrusion 25 has anexterior diameter which is adapted to permit the lower end of the columnmember i to be shrunk t thereon, and a shoulder 2'! about the base toprovide a seat for the end of the column member. If desired a weld 28can be used to reinforce the connection as shown. A hole 29, extendsthrough the protrusion 25 and the yoke-like body 2Q. trusion 25 tapersdownwardly to a minimum diameter at the extremity as shown, the minimumdiameter being somewhat less than the diameter of a pilot hole |29, inthe earth formation in which the drill post assembly is to be anchored.The conical protrusion 25 has a counterbore 3e which extends practicallythe full length of the protrusion, the diameter being such as to providea sliding fit with the exterior surface 23 of the collet to preventlateral movement but permit axial movement between the respective parts.The collet is arranged, during the inoperative position, to engage thecounterbore 3l? of the protrusion 2S for a distance of approximatelyfourfifths the length of said counterbore. At the base of thecounterbore 35, a shoulder 3l serves for the abutment of the compressivespring I8. A bore 32 of slightly greater diameter than the diameter ofthe draw bolt, extends from the shoulder 3l through the yoke-like member2t. A .boss 33 arranged about the bore 32 and on the inner surface ofthe yoke-like member has two radial grooves to receive lugs 35 on thebottom of a washer Sil, as shown in Fig. 3.

The draw bolt Il has at one end a frusto-conical head 3S having anexterior surface tapered upwardly at an angle of approximately tendegrees with the axis, or an included angle of twenty degrees, as shownin Fig. 2 of the drawing. The frusto-conical head is adapted tooperatively engage the interior conical surface 2G of the expensioncollet, the contacting surfaces of each being case-hardened to providegood wear. The other end of the draw bolt has a threaded part 3l toreceive a draw nut 38 and has a longitudinal groove 39 which is arrangedto engage protrusion 4S of Washer 34. A transverse hole is arranged inthe bolt near the end of the threaded portion to receive a Cotter pin 4IThe washer 34 has an internal diameter slightly larger than the diameterof the draw bolt, and the two lugs 35 on the lower surface fit thegrooves of boss 33, while the internal protrusion 13! is arranged toslidably engage the groove 39 of the draw bolt. The bolt I 1 is thusmounted for axial,

The frusto-conical pronon-rotative, movement relative to yoke 24. Upwardmovement of the draw bolt relative to the yoke causes the bolt to exerta force on the collet, which force may be resolved into a radialcomponent tending to spread the collet segments and an axial componenttending to raise the collet against the opposition of spring I 8.

All diameters of the elements are concentric with respect the axis ofthe drill post assembly, as can be seen from the drawing.

n the assembly of the anchoring means I I, the first portion I4 isslidably arranged within the protrusion 26 of the second portion I5, asheretofore set forth, the compressive spring I8 being arranged withinthe collet to abut at one end the shoulder 2|, and to abut at the otherend shoulder 3| of the tubular protrusion 26. The spring I 8 whenpositioned in the assembly is compressed to approximately two-thirds itsfree length and thus serves, to maintain the collet in extendedrelationship with respect to the conical protrusion 2S, and serves toprevent telescoping action therebetween as the draw nut is first turned.lThe draw bolt il passes within the spring, the conical head 35 being incontact with the tapered surface 2B of the collet and the threaded endextends through the wall of the yoke-like body 24 to receive the washer365, draw nut 38 and cotter pin 4I. It can be seen that the arrangementof the washer serves to prevent rotation of the draw bolt as the drawnut is turned thereon. The Cotter pin prevents the draw nut from beingunintentionally removed from the draw bolt.

To set up the drill post assembly the pilot hole 29 is first drilled inthe rock or the earth formation in which it is desired to anchor theassembly, the pilot hole being conveniently formed by means of ahand-held machine or" the sinker type. While the dimensions of the pilothole vary in accordance with the size of the drill post assembly, apilot hole approximately 21/2 in diameter and l ft. deep is satisfactoryfor a drill post assembly having a 31/2" diameter column niember i@extending to a distance of approximately e ft. above the ground line.The first portion I; and part of the conical tubular portion 26 areinserted in the hole so that contact is made between the edge of thepilot hole opening and the portion 26, as shown in Fig. 2. The draw nut38 is then turned, causing the draw bolt to be drawn upwardly and expandthe collet as a result of the action of the conical head 36 on theconical surface 28 of the collet; up to this stage, the axial componentof force transmitted through the collet i5 is insufcient to overcome thecompressive force of spring I 8 and relative movement between the colletand second portion 24 is prevented.

After the collet has been expanded a predetermined amount, such beingthe amount of expansion necessary to cause the serrations 22 to contactthe wall of the pilot whole, further turning of the draw nut will causethe serrations t0 bite into the wall of the pilot hole until furtherexpansion of the collet is effectively resisted by the walls of thehole, after which the collet or rst portion i!! in eifect becomesrigidly associated with the draw bolt Il. Further turning of the drawnut meets with increased resistance and causes the second portion I5 tobe drawn toward the rst portion I4, with the result that the conicaltapered protrusion 2s moves downward and becomes irmiy wedged in theopening of the pilot hole, thereby giving rigid support to the drillpost assembly. It can be seen that the spring I8 will be compressedduring the latter stages of the anchoring operation, after the turningforce on nut 38 has been increased to overcome the increased resistance.

To knock down the drill post assembly it is merely necessary to turn thedraw nut in the opposite direction which results in the release of theconical tubular portion 26, which is thus forced from the pilot hole byaction of spring I8. Normally, there will be little tendency for theconical head 3B of the draw bolt to become wedged within the conicalportion 20 of the collet. However, should such occur a rod can be passedthrough the column member and hole 29 of the second portion, so that theend of the draw bolt can be tapped slightly and thus break any wedgingaction at the other end.

What is claimed is:

1. Anchoring means for a drill post adapted for rigid fixation in apilot hole, comprising a first portion having an expansible colletsection, a second portion positioned between the rst portion and thedrill post, said second portion having an external conical surfacetapering in the direction of the first portion and having a minimumdiameter less than the diameter of the pilot hole, said rst portionbeing slidably arranged in part within the second portion, resilientmeans maintaining the first portion and the second portion inopposition, a draw bolt extending through the rst and second portionsand having a conical portion tapering in the direction of the secondportion, and means operable to move the draw bolt in the direction ofthe second portion thereby forcing the conical surface of the secondportion further into the pilot hole after the expansible collet sectionhas been expanded by the conical portion of the draw bolt to fullyengage the pilot hole.

2. Anchoring means for a column member for aiixing said column member ina hole, said anchoring means including a first portion having anexpansible collet section, a second portion positioned between the firstportion and said column member and being aflixed to the latter andhaving an external surface tapering in the direction of the rst portionsaid tapered surface being of size to permit partial entry thereof intothe anchoring hole, said rst portion arranged in part within the secondportion for axial movement relative thereto, yieldable means interposedbetween the first and second portion resisting axial `movementtherebetween, and means operable for expanding the expansible colletsection and forcing the second portion toward the first portion afterthe collet section is expanded a predetermined amount said latter meansincluding a draw bolt having a tapered head whereby the expansiblecollet section is forced into engagement with the wall of the anchoringhole.

3. Anchoring means for a column member for affixing said column memberin a hole, said anchoring means including a first portion having anexpansible collet section, a second portion positioned between the firstportion and said column member and being affixed to the latter andhaving an external surface tapering in the direction of the rst portionsaid tapered surface being of size to permit partial entry thereof intothe anchoring hole, said first portion arranged in part within thesecond portion for axial movement relative thereto, resilient meanscompressively interposed between the rst portion and the second portionfor resisting axial movement therebetween, and means for expanding thecollet section a predetermined amount and forcing the second portiontoward the rst portion after the collet section is expanded saidpredetermined amount said latter means including a draw bolt having atapered head whereby the expansible collet section is forced intoengagement with the wall of the anchoring hole.

4. Anchoring means for a column member for affixing said column memberin a hole, said anchoring means including a rst portion having anexpansible collet section, a second portion positioned between the firstportion and said column member and being rigidly aixed to the latter andhaving an external conical surface tapering in the direction of thefirst portion said tapered surface being of size to permit partial entrythereof into the anchoring hole, said first portion being slidablyarranged in part within said second portion, guiding means preventingrotary movement of the first portion relative the second portion,resilient means maintaining the rst portion and the second portion inopposition, and draw means for expanding the collet section intoengagement with the wall -of the anchoring hole including a taperedconical surface tapering in the direction of the second portion, saiddraw means being further arranged for forcing the second portion towardthe rst portion after the collet section is expanded into engagementwith the wall of the anchoring hole.

5. An anchoring means as claimed in claim 4 wherein said expansiblecollet section is provided with a serrated external surface.

EARL B. LEAR.

REFERENCES CITED The following references are of record in the le ofthis patent:

UNITED STATES PATENTS Number Name Date 725,085 Jacob Apr. 14, 1903950,492 Pleister Mar. 1, 1910 1,137,443 Ackerman Apr. 27, 1915 1,805,731Beckwith May 19, 1931 2,442,113 Beijl May 25, 1948 FOREIGN PATENTSNumber Country Date 444,623 Great Britain of 1934

